Globule formation of fine particles using a new high-temperature air-jet-flow system

High-temperature air jets are widely used in such processes as heating, drying and powder treatment; however, the flow and heat-transfer characteristics of high-temperature air jets have not yet been fully clarified. in purpose of this study is to improve the performance of surface fusing, or the globule-formation system of fine thermoplastic particles. First, we experimentally investigate the velocity and thermal characteristics of high-temperature air jets from a round nozzle and a new “triple-concentric” nozzle as well as the characteristics of heat-transfer from a high-temperature air jet to fine particles. Next, we investigate the globule-formation characteristics. Consequently, we can clarify the relationship between heat transfer and globule formation. We also examine the effect of nozzle structure on the performance of globule formation. The results show that the new globule-formation system offers higher performance, along with approximately 5.3 times greater energy efficiency than the previous system.